zalando / skipper / 31731573193

81%

Build Type

push

github

Committed by web-flow

Commit Message

filters: annotate routes with application label (#4147)

## Change

Pass the Kubernetes routing object's configured label value into Skipper
route context by adding `annotate("Application", <label value>)` to
generated routes. The label *key* to read the value from is configurable
via `-kubernetes-application-annotation-label` (e.g. `application`,
`app.kubernetes.io/name`), but the annotation key written to the route's
StateBag is always the fixed `"Application"` constant.
The annotation is sourced from:
- `Ingress.metadata.labels.application`
- `RouteGroup.metadata.labels.application`

Covered route generation paths:
- Ingress normal `spec.rules[].http.paths[]` routes via
`addEndpointsRuleV1`
- Ingress custom routes from `zalando.org/skipper-routes` via
`addExtraRoutes`
- Ingress `spec.defaultBackend` routes via `ingressV1Route`
- RouteGroup implicit routes via `implicitGroupRoutes`
- RouteGroup explicit routes via `explicitGroupRoutes`

The filter is prepended so `annotate("Application", ...)` runs before
later route filters that may read annotations from the request
`StateBag`. If a user explicitly adds their own `annotate("Application",
...)` later in the route, that annotation still wins because `annotate`
overwrites the same key.

The feature is off by default:
`-kubernetes-application-annotation-label` defaults to an empty string,
so no `annotate` filter is added unless an operator explicitly sets a
label key (e.g. `application` or `app.kubernetes.io/name`).

The annotation is intentionally added to real routes generated from
Ingress and RouteGroup objects, not to synthetic helper routes such as
HTTPS redirects or catch-all shunt routes, to avoid attributing proxy
control traffic to an application.

## Known gap
Ingress routes using `zalando.org/skipper-backend: <forward>` may still
lose the generated annotation on normal/custom paths because
forward-backend handling clears route filters in `applyBackend`. This PR
leaves that existing forward-b... (continued)

Coverage Stats

26 of 30 new or added lines in 7 files covered. (86.67%)

473 existing lines in 11 files now uncovered.

29147 of 36141 relevant lines covered (80.65%)

78484.27 hits per line